Horticultural lighting unit



FIG. 1 is a front elevation view of a horticultural lighting unit according to the design;

FIG. 2 is a rear elevation view thereof;

FIG. 3 is a left side elevation view thereof, the right side elevation view being a mirror image of FIG. 3;

FIG. 4 is a top plan view thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top rear perspective view thereof; and,

FIG. 7 is a bottom front perspective view thereof. 

CLAIM The ornamental design for a horticultural lighting unit, as shown and described. 